CRYSTAL-STRUCTURE AND PROPERTIES OF A NEW COPPER(II) COMPLEX OF DIOXOCYCLAM APPENDED WITH 8-METHYLQUINOLINE (DIOXOCYCLAM EQUALS 1,4,8,11-TETRAAZACYCLOTETRADECANE-5,7-DIONE)

A new macrocyclic dioxotetraamine ligand ethyl)-1,4,8,11-tetraazacyclo tetradecane-5,7-dione (H2L) has been synthesized. The resulting dioxoc yclam readily forms a 1:1 Cu(II) complex (Cut) with concomitant double deprotonation of the ligand. Cut has been isolated as single crystals and the structure was determined by X-ray diffraction analysis. CuL.5 H(2)O (1.5H(2)O) crystallizes in monoclinic crystal system, P2(1)/n sp ace group with a = 12.979(2), b = 13.638(6), c = 13.634(4) Angstrom, b eta = 103.02(2)degrees, V = 2351(2) Angstrom(3), M-r = 521.07, Z = 4, D-calc = 1.472 g/cm(3), mu = 9.78 cm(-1), F(000) = 1100, room temperat ure, and R = 0.039, R-w = 0.042 for 2137 observed reflections with I > 3 sigma(I). In complex 1, the Cu atom is five coordinate to form a di storted square pyramid in which N(5) of the quinoline pendant is at th e apical site. The Cu-N(5) bond distance (2.262(4) Angstrom) is longer than the basal average Cu-N bond lengths (1.994(4) Angstrom). The beh avior of Cut in solution has been studied further with ESR, UV-Vis and cyclic voltammetry.